Metallurgical furnace.



U. WEDGE.

METALLURGICAL FURNACE. APPLICATION 'FILED JAN. 15, 1913. RENEWED JULY 1, 1915.

l,1?0,876. Patented Feb. 1, 1916.

UTLEY WEDGE, OFARDMORE, PENNSYLVANIA.

METALLURGICAL FURNACE.

Specification of Letters Patent.

Patented Feb. 1, 1916.

Application filed January 15, 1913, Serial No. 742,151. Renewed July 1, 1915. Serial No. 37,586.

To all whom it may concern Be it known that I, UTLEY WEDGE, a citizen of the United States, residing at Ardmore, Pennsylvania, have invented certain Improvements in Metallurgical Furnaces, of which the following is a specification.

My invention'ielates to furnaces for the roasting or desulfurization of the ores of zinc, nickel or other metals, the purpose of my invention being to eifect the complete elimination of the sulfur and the recovery of all or practically all of the sulfurous gas, without contamination of the same with carbonaceous products of combustion so that they can be utilized in subsequent processes of manufacture, as, for instance,'in the manufacture of sulfuric acid.

The accompanying drawing shows in vertical section a furnace constructed in accordance with my invention.

The furnace structure 1s of the type of those heretofore patented by me and comprises an outer wall 1, usuallylof circular form, and inclosing a series of superposed hearths, of which, in the present instance, there are thirteen, numbered consecutively from top to bottom with the numerals 2-to 14, inclusive, the corresponding treating chambers being numbered 2* to 14 inclusive. The furnace has a roof 15 on which the ore is first placed and there maintained in a condition of agitation by suitable stirrers so as to dry or heat the same preparatory to feeding it into the top treating chamber 2 of the furnace through a suitably luted feed passage 16. Each of the hearths has a central opening for the reception of a central vertical shaft 17, the latter consisting, by preference, of a metallic cylinder covered with fire clay or other refractory material and provided at the bottom with any suitable means for imparting rotation to it.

The furnace is divided into upper and lower members, each containing as many treating chambers as may be necessary in order to give the best results with the particular ore under treatment. The upper or primary member, in the present instance,

comprises the treating chambers 2 to 10, inclusive, and the lower or secondary member comprises the treating chambers 11 to 14: inclusive, said upper and lower members being separated from one another by the hearth 10.

Each of the chambers of the furnace contains one or more rabble arms 18, carried by and rotating with the central shaft 17 each of these rabble arms in practice being provided with a series of depending rabbles whereby the material lying upon the hearth. of the chamber is stirred or agitated and at the same time is fed over the hearth either from the inner to the outer portion of the same or from the outer to the inner portion, the material dropping from hearth to hearth through suitably located passages 19, located adjacent to the outer or inner portion of the hearth, depending upon the direction of travel of the material over the hearth. The openings 19 in the dividing hearth 10, however, are provided with rotary valves 20 having pockets therein, which, when the mouth of the pocket is uppermost, receive the ore from thehearth 10 and when the mouth of the pocket is lowermost discharge said ore onto the hearth 11 below, the valves at all times, however, preventing any flow of gas from one member of the furnace to the other. In place of these rotating valves, however, any other available means for sealing, against the flow of gas, the ore passages between the treating chambers 10 and 11 may be employed.

The products of combustion are introduced through a suitable pipe or flue 30 into the top chamber 11 of the lower member of the furnaceeither in the form of natural gas, ignited hydrocarbon oil, or the products of combustion from a suitably located adjacent fire place burning coal, coke, or other solid carbonaceous fuel, and these products of combustion circulate downwardly through the chambers 11*, 12* 13* and 14 and finally escape from, the latter chamber into an annular flue 21 surrounding the lower portion of the furnace.

Heated air is admitted to the lowermost chamber 10 ofthe upper member of the furnace from an annular flue 22 surrounding that portion of the furnace in which the said chamber 10 is located and the gases may be withdrawn from one or more of a series of chambers in the upper portion of the furnace through independent fiues 2 3 4*, 5 and 6 the outflow of gas through either of these flues being suitably regulated by a damper 23 therein and the escaping gases being collected in a common flue 24, whereby they are conveyed to the point where they are to be subsequently utilized. The draft through the upper member of the furnace is therefore upward, while that through the lower member of the furnace is downward, and said chambers in the lower member of the furnace are supplied with carbonaceous products of combustion while the chambers of the upper member of the furnace are supplied with heated air, the carbonaceous products of combustion being excluded therefrom. The gases may pass from chamber to chamber of either member of the furnace through the same openings 19 which provide for the passage of the ore, but it is preferable, in most cases, to provide special gas passages in flue boxes or casings :26 inserted at suitable intervals in the walls of the furnace, these passages permitting communication between the upper portions of adjoining treating chambers so that the flow of gas will not be obstructed by the flow of the I powdered ore, and the carrying off of the finer particles of the ore by the gas in the form of what is known as flue dust will be reduced to a minimum.

Each of the rabble arms in the chambers of the upper member of the furnace has therein passages for the circulation of air through the arm, each rabble arm communicating with a suitably partitioned head 27 on the interior of the shaft so that air entering the upper portion of said head will be directed outwardly through the upper portion of the rabble arm and returned, through the lower portion of the arm, to the. lower portion of the head 27, and from the latter, through a suitable connecting pipe 28, to the head 27 of the rabble arm in the next treating chamber of the furnace, the operation being repeated in each' rabble arm until the heated air finally escapes from the lowermost head 27 through a pipe 29 into the uppermost chamber 11 of the lower member of the furnace, wherein it combines with the products of combustion from the pipe or flue '30 so as to produce a clean oxidizing flame in said chambers of the lower furnace member.

The combustion of the sulfur in the ore is actively maintained by contact with the heated, air in the chambers of the upper member of the furnace and the resulting sulfurous gas is discharged from one or ,more of the upper chambers of the series into the flue 24. In case too high a degree of heat is likely to result in the upper chambers of the furnace because of the combustion of the sulfur in the ore the withdrawal of the sulfurous gases may begin at a chamber some distance below the top chamber of the series, for lnstance at the chamber 6 and a portion of the gases may also be withdrawn from each of the chambers above the same so as to temper the heat in the upper chambers of the furnace, whereby, in ores containing lead In the drawing I have shown cooling devices in connection with the rabble arm in the lowermost chamber of the lower member of the furnace and such cooling devices may be used on all of the rabble arms in this member of the furnace, if desired.

As but a small amount of sulfur remains in the ore when the latter enters the lower member of the furnace, the percentage of sulfur gas escaping into the air with the heating gases from said lower member of the furnace will not exceed that permitted by the sanitary regulations under which furnaces of this type must be operated, in certain localities, and, on the other hand, the elimination of the sulfur to the fullest possible extent, by reason of the direct contact of the heated products of combustion with the ore in the lower member ofthe furnace, will, especially in the case of zinc concentrates, result in a calcine of most desirable quality for subsequent metallurgical treatment.

In connection with the furnace I use, by preference, an air heater in which the waste products of combustion from the lower member of the furnace are caused to heat theair which is admitted to the upper member of the furnace but such heater forms no essential part of my present invention, but constitutes the subject of a separate application for patent filed by me on the fourth day of January 1913, Serial No. 740,105.

I claim:

1. A metallurgical furnace having primary and secondary members, means for introducing into said secondary member products ofcombustion derived from fuel independent of the furnace charge, means for causing said products of combustion to flow through the secondary member in one direction, and means for causing air to flow through the primary member in the opposite direction.

2. A metallurgical furnace having primary and secondary members, each with a series of treating chambers therein, means for supplying to the secondary member of the furnace products of combustion derived from fuel independent of the furnace charge, means for causing said products of combustion to flow through the chambers of the secondary member of the furnace in one direction, and means for causing air to flow through the chambers of the primary member of the furnace in the opposite direction.

3. A metallurgical furnace having primary and secondary members, means for causing the material to be treated to flow in the same direction through both members, means for conveying to the secondary member products of combustion derived from fuel independent of the furnace charge, means for causing said products of combusof the furnace in one direction, and means for causing air to flow through the primary 'member of the furnace in the opposite directlon. v

4. A metallurgical furnace having primary and secondary members, means for causing the material to be treated to flow in one and the same direction through both members, means for supplying to the secondary member of the furnace products of combustion derived from fuel independent of the furnace charge, means for causing said products of combustion to flow through the secondary member of the furnace in the same direction as that of the flow of material therethrough, and means for causing air to flow through the primary member of the disposed between the primary and secondary members of the furnace and serving to prevent passage of said products of combustion from the secondary member to the primary member.

6. A metallurgical furnace having primary and secondary members superposed one upon the other and each having a series of superposed treating chambers, means for supplying air to the treating chambers of the primary member, means for supplying to the treating chambers of the secondary member products of combustion derived from fuel independent of the furnace charge, rabble arms in the treating chambers of the primary member, and means for conveying air through said rabble arms in succession and discharging the air thus heated into the products of combustion in the secondary member of the furnace for admixture therewith.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

UTLEY WEDGE. Witnesses:

KATE A. BEADLE,

HAMILTON D. TURNER. 

